The term "stent" is generally used to describe endoprosthetic devices which are implanted in blood vessels or other anatomical passageways of the body for the purpose of treating stenoses, aneurysms, occlusions, etc. Typically, such stents are implanted in blood vessels to maintain dilation and patency of an occluded region of blood vessel, or to bridge a weakened or aneurysmic region of blood vessel. On the other hand, some typical non-vascular applications of such stents are for the treatment of constrictions or injuries to the gastrointestinal tract (e.g., esophagus), ducts of the biliary tree (e.g., common bile duct) or anatomical passageways of the genitourinary tract (e.g., ureter, urethra fallopian tube, etc.).
Most stents are initially disposed in a compact configuration of relatively small diameter, whereby the stent may be mounted upon or within a delivery catheter for insertion and transluminal advancement into the desired anatomical passageway. Thereafter, such stents are radially expandable to a larger "operative" diameter which is equal to or slightly larger than the diameter of the blood vessel or other anatomical passageway in which the stent is to be implanted. When radially expanded to such operative diameter, the stent will typically become released from the delivery catheter and embedded or engaged to the surrounding wall of the blood vessel or other anatomical passageway.
Some stents are covered with tubular sleeves, in which case they are typically referred to as a "stented graft".
In general, stents and stented grafts fall into two major categories--a) self-expanding and b) pressure-expandable. Those of the self-expanding variety may be formed of resilient or shape memory material (e.g., spring steel or nitinol.TM.) which is capable of self-expanding from its first (radially compact) diameter to its second (operative) diameter without the exertion of outwardly-directed force against the stent or stented graft. Examples of such self-expanding stents and stented grafts are set forth in U.S. Pat. Nos. 4,655,771 (Wallsten, et al); 4,954,126 (Wallsten); 5,061,275 (Wallsten, et al); 4,580,568 (Gianturco); 4,830,003 (Wolf, et al); 5,035,706 (Gianturco, et al); 5,330,400 (Song) and 5,354,308 (Simon, et al) and Foreign Patent Publication Nos. WO94.backslash.12136; WO92.backslash.06734 and EPA183372. Those of the pressure-expandable (i.e., "passive expandable") variety may be formed of plastically deformable material (e.g., stainless steel) which is initially formed in its first (radially compact) diameter and remains stable in such first diameter until such time of outwardly directed pressure is exerted upon the stent or stented graft to cause radial expansion and resultant plastic deformation of the stent or stented graft, to its second (operative) diameter. Examples of such pressure-expandable stents and stented grafts are set forth in U.S. Pat. Nos. 5,135,536 (Hillstead); 5,161,547 (Tower); 5,292,331 (Boneau); 5,304,200 (Spaulding); 4,733,665 (Palmaz); 5,282,823 (Schwartz, et al); 4,776,337 (Palmaz); and 5,403,341 (Solar) and Foreign Patent Publication Nos. EPA480667; and WO95.backslash.08966.
In many applications, careful positioning and firm implantation of the stent or stented graft is critical to the successful treatment of the underlying medical problem. In this regard, the delivery catheter which is utilized to accomplish the positioning and implantation of the stent or stented graft is an important aspect of the overall system. Various types of delivery catheters for stents and stented grafts have been previously known, including those described in U.S. Pat. Nos. 4,665,918 (Garza, et al); 4,733,665 (Palmaz); 4,739,762 (Palmaz); 4,762,125 (Leiman, et al); 4,776,337 (Palmaz); 4,838,269 (Robinson, et al); 4,994,071 (MacGregor); 5,037,427 (Harada, et al); 5,089,005 (Harada); 5,102,417 (Palmaz); 5,108,416 (Ryan, et al); 5,141,498 (Christian); 5,181,920 (Mueller, et al); 5,195,984 (Schatz); 5,201,901 (Harada, et al); 5,269,763 (Boehmer, et al); 5,275,622 (Lazarus, et al); 5,290,295 (Querals, et al); 5,306,294 (Winston, et al); 5,318,588 (Horzewski, et al); 5,344,426 (Lau, et al); 5,350,363 (Goode, et al); 5,360,401 (Turnland); 5,391,172 (Williams, et al); 5,397,345 (Lazarus); 5,405,380 (Gianotti, et al); 5,443,452 (Hart, et al); 5,453,090 (Martinez, et al); 5,456,284 (Ryan, et al); and 5,456,694 (Marin, et al) and Foreign Patent Publication Nos. EP-0308-815-A2; EP-0335-341-A1; EP-364-787-A; EP-0442-657-A2; EP-482976-A; EP-0505-686-A1; EP-0611-556-A1; EP-0638-290-A1; WO94.backslash.15549; WO95.backslash.01761; GB2196-857-A; DE3042-229; and DE3737-121-A. Generally, the attributes which are desirable of any delivery catheter which is to be used for placement and implantation of stents or stented grafts, are as follows:
a) maintain minimal diameter during insertion to avoid unnecessary trauma and/or difficulty of placement; PA1 b) include radiopaque markings at appropriate locations to facilitate precise visualization and positioning of the delivery catheter to ensure that the stent or stented graft is implanted at the desired location; PA1 c) reliable and reproducible expansion of the stent or stented graft to its full operative diameter, without regional or localized variations in the degree or completeness of such expansion; PA1 d) reliable and reproducible disengagement or release of the stent or stented graft from the catheter body; PA1 e) ability to withdraw and remove the delivery catheter without disturbing the newly implanted stent or stented graft; and, PA1 f) ability to easily check for leakage of biological fluid (e.g., blood) outside of a stented graft (i.e., an "endoleak") after the stented graft has been delivered and implanted within a body lumen. PA1 a) a portion of the catheter being formed of separate tubular members upon which opposite ends of a radially expandable balloon are mounted such that movement (e.g., longitudinal, rotational) movement of one of such members relative to the other will cause the balloon to be tightened (e.g., longitudinally drawn, rotatably twisted) to a taut configuration when the balloon is in its deflated state, thereby eliminating or minimizing loose or protrusive balloon material which may interfere with subsequent retraction and removal of the delivery catheter; and/or, PA1 b) a non-tapered or minimally-tapered balloon which is usable to radially expand the tubular intraluminal prosthesis, said balloon being mounted on the body of the delivery catheter and comprising: PA1 c) a loader assembly for facilitating introduction of the distal portion of the catheter and a radially-compact intraluminal prosthesis mounted thereon, into a tubular introducer. Such loader assembly may comprise a tubular sheath which is advancable over the radially compact intraluminal prosthesis mounted on the catheter body, and which is directly engageable to the proximal end of an introducer so as to facilitate subsequent advancement in introduction of the radially compact intraluminal prosthesis into the lumen of the introducer; and/or, PA1 d) one or more radiographic contrast medium outflow apertures in communication with a radiographic contrast medium infusion lumen extending longitudinally through the catheter, said outflow aperture(s) being positioned on the catheter at a location whereby radiographic contrast medium may be infused through the lumen and out of the outflow aperture(s) into the body lumen wherein the endoluminal prosthesis has been implanted, at a location upstream of the endoluminal prosthesis, such that said radiographic contrast medium will migrate outside of the endoluminal prosthesis if endoleak(s) exist whereby endogenous fluid flowing through the body lumen is seeping or leaking around the endoluminal prosthesis due to inadequate or imperfect implantation and abutment of the endoluminal prosthesis against the body lumen in which it is implanted. PA1 a) an embedded radiopaque marker which comprises a ring or segment of radiopaque material which has been melted or otherwise embedded within the wall of the introducer sheath so as to be fully surrounded or encapsulated by the material of the introducer sheath, while remaining visible by radiographic means; and/or, PA1 b) a valving assembly (e.g., "valving head") mounted on the introducer sheath in alignment with the lumen of the introducer sheath, said valving assembly comprising:
None of the previously-known delivery catheter systems have been clearly optimal for all types of stents and stented grafts. Accordingly, there remains a need in the art for a design and development of improved delivery catheter systems for at least some types of stents and stented grafts.